Microelectronic devices, such as semiconductors or integrated circuits, can include millions of electronic circuit devices such as transistors, capacitors, etc. To further increase the density of devices found on integrated circuits, even smaller feature sizes are desired. To achieve these smaller feature sizes, the size of conductive lines, vias, and interconnects, gates, etc. must be reduced. Reliable formation of multilevel interconnect structures is also necessary to increase circuit density and quality. Advances in fabrication techniques have enabled use of copper for conductive lines, interconnects, vias, and other structures. However, electromigration in interconnect structures becomes a greater hurdle to overcome, with decreased feature size and the increased use of copper for interconnections. Such electromigration may adversely affect the electrical properties of various components of the integrated circuit.
Tantalum nitride (TaN) is a copper barrier at film thicknesses greater than 10 Å, where the film is continuous. However, at nodes below 22 nm, TaN deposited by thermal atomic layer deposition (thermal ALD) is not a good copper barrier layer. Therefore, there is a need for new methods for depositing films that are effective copper barriers.